Piston



H. BECKER PISTON Filed April 16, 1952 May 19, 1936.

VV// 7//// y( 1/1? km a J AM A v e Patented May 19, 1936 UNITED 'srATEs PISTON Heinrich 'Booker', Ab to Maschinentbrik A G rmany, assisnoburg-Nurnberg A. G.,

Augsburg, Germany, a corporation of Germany Application an-u s, 1932, Serial No. 605.557 In Germany May 4, 1931 Claim. A (CI. 123-176) This invention relates to engine pistons and more particularly to the type of piston in which there is an internal' chamber !or cooling medium.

One object of the invention is' the provis'ion oi 5 a piston of the character mentioned having a cooling medium chamber extending along' the wrist pin bearing wall in such a way as to provide Ior effective cooling of the wrist pin hearing surface.

Another object of the invention is the provision of an engine piston adapted to be'cooled by a flow of cooling medium, the piston having a chambercxtending to the piston head and also partly dened by a wrist pin hearing wall which extends across the piston.

Another object of the invention is the provision of a piston of the character mentioned ha V g a cooling chamber which is divided by a partitifo so that oil or other cooling medium 'isnsupplid to the portion of the chamber deflned in part by the wrist pin hearing wall, the piston head portion of the chamber being connected to the outlet passage. V i i Other, objects and advantages of the invention will be apparent rrom 'the following description,

the appended claims and the accompanying draw- The 'drawing' shows a central vertical 'section of -a piston embodying the -present invention.

Referring more particularly to the drawing by reference letters, the piston as herein shown is adapted for use in an internal combustion engine, the piston'beinghollow or chambered so as to provide for a. flow of cooling medium. The piston 5 of the present invention' is particularly adapted for two cycle engines, in which every second stroke is a working stroke, and in which no change 4 in pressure direction takes place in the wrist pin hearing. In such engines itis only that side of 9 ,the wrist pin hearing adJacent thepiston head to 'which the forces are applied, and it has been dii'- flcult to adequatelylubricate this hearing in .ac'

cordance with prior practices. It has also been dimcult to adequately design the hearing to take 45 up the great stresses to which it is subjected and which resuit trom thepressures o! the burning gaes on the piston head. In-the case of Dieselengines for example, having a 'relatively-small surface contact between the wrist pin and the 50 piston, the forces are oten'so great as to cause the wrist pin hearing to run very hot, and resultin bursting of the piston.

In accordance with the present invention, the

wrist pin hearing surface ot the piston is efltec ;4 tively cooled and adequately proportioned so as to operate satistactorily under the large-pressure strains to which it is subiected, especially at full load and high speed, The piston body A is provided with a wrist pin hearing wall B which extendsacross the piston, its end portions being 5 provided by the circular openings in the cylindrical wall which receive the ends of the wrist pin. The hearing wall B is preterably cast integrally with the piston walls and with the piston head. and

as shown, provides a large size semi-cylindrical o hearing surface extending the tull piston diameter. The upper end ot the connectingrod may be inserted through the open lower end of the piston and fixed to a flat part ot the wrist pin which is passed through the openings in the piston 15 skirt. The piston is hollow between the piston head and the hearing wall B, providing a space for cooling liquid such .as' oil or other cooling medium. This cooling medium may be 'supplied to the lower part of the cooling medium chamber 20 through a passage a, while an outlet passage e is provided in the opposite' side of the pistonwail, this outlet passage extending up to a point adjacet the piston head. The cooling liquid is forced to the inlet passage a by any suitable means. The 25 cooling medium chamber is preferably divided into two spaces by means of a partition wall d arranged between the piston head and the -wrist pin hearing wall B. An openin !I is provided in the partition wall so that the cooling medium may 30 flow from the wrist pin chamber b to thepiston head chamber c.

It will be appa'rent that as the cooling medium is supplied to the chamber portion b it will absorb heat from the wrist pin hearing wall B. The cooling medium, in its passage through the piston, will then flow up through the opening g tothe piston head chamber portion c and absorb heat !rom the piston head before it flows out through the outlet passage e. 40

While the form oi' construction herein described constitutes a preierred embodiment ot the inven-` tion, it is to be understood that the invention is not limited to this precise form, and that changes may be made therein without' departing fromthe scope of the invention which is defined in the appended claims.

What I claim is:

1'. An engine piston having a head wall, a wrist-- pin hearing wall and a skirt wall, said piston I 'having a chamber !or cooling liquid extending verse oi' the piston azis between the wall and plying cooling liquid to a point in said chamber at one side of said partition wall adjacent the wrist pin hearing wall, and a. liquid withdrawing passage extending from said chamber from a point adjacent the other side of' said partition wall.

2. An 'engine piston having a wrist pin hearing wall provided as a part thereof and providing a cylindrically concave hearing surface extending across the piston, said piston havinga. chamber for the circulation of cooling medium extending up to the piston head and extending along said wrist pin bearing wall, a partition wall in said chamber provided between the piston head and the hearing `wal1 and partitioning said chamber into a hearing wall portion and a piston head portion, said partition having an opening therein, a cooling. medium supply passage in communication with said bearing wall portion of the chamber, and an outlet passage for the cooling medium in communication with said piston head chamber portion.

3. An engine piston having a wrist pin bearing wall as an integral part thereof and providing a cylindrically concave bearing surface extending entirely across the piston for direct bearing engagement with substantially the entire upper half of the wrist pin, said piston having a chambe r for cooling liquid which extends up to the piston head and which also extends continuously along said wrist pin hearing wall, a supply pipe for supplying cooling liquid to a point in said chamber adjacent said hearing wall, and a liquid withdrawing passage extending from said chamber.

4.-An engine piston having a wrist pin hearing wall as an integral part thereof and providing a cylindrically concave hearing surface extending entirely across the piston rod opening for direct bearing engagement with substantially the entire upper half of the wrist pin, said piston having a chamber for cooling liquid extending alongsaid wrist pin hearing wall, a supply passage for continuously supplying cooling liquid to a point in said chamber adjacent said hearingpiston head and which also extends continuously along said wrist pin hearing wall and of considerable length in the direction of the piston axis, a. supply passage formed in the piston wall at a side of said concave hearing surface for supplying cooling liquid to a point in said chamber adjacent said bearing wall, and a liquid withdrawing passage extending from said chamber.

HEINRICH BECKER; 

